Olefin Hydroarylation Catalyzed by (pyridyl-indolate)Pt(II) Complexes: Catalytic Efficiencies and Mechanistic Aspects

A series
of Pt­(II) complexes of the type (N–N)­PtPh­(SR2) (N–N
= 2,2′-pyridyl-indolate) were prepared,
and their performance as catalysts for the hydroarylation of olefins
was assessed. Evidence that the catalysis is homogeneous and is Pt-mediated
is provided by control experiments with added hindered base (2,6-di-tert-butyl-4-methylpyridine) and Hg(0). Two potential catalytic
intermediates, (tBuPyInd)­PtPh­(C2H4) and (tBuPyInd)­Pt­(CH2CH2Ph)­(C2H4), were synthesized,
and their catalytic efficacy was explored. Additionally, decomposition
and deactivation pathways, including styrene formation via β-hydride
elimination and ligand reductive demetalation, were identified.

本研究合成了一系列通式为(N–N)PtPh(SR₂)的铂(II)配合物，其中配体N–N为2,2'-吡啶基吲哚啉（2,2′-pyridyl-indolate），并评估了其作为烯烃氢芳基化催化剂的催化性能。通过添加位阻碱2,6-二叔丁基-4-甲基吡啶（2,6-di-tert-butyl-4-methylpyridine）与零价汞（Hg(0)）的对照实验，证实该催化反应为均相催化且由铂介导。本研究合成了两种潜在的催化中间体：(tBuPyInd)PtPh(C₂H₄)与(tBuPyInd)Pt(CH₂CH₂Ph)(C₂H₄)，并探究了其催化效能。此外，本研究还明确了该体系的分解与失活路径，包括通过β-氢消除生成苯乙烯以及配体还原脱金属反应。